We already know that migratory birds use their recognition of magnetic fields to travel south during the winter. Certain species of mice and rats set up their nests along magnetic field lines. And dogs also have an awareness of the earth’s magnetic field, which studies have shown they use, for whatever reason, to relieve themselves along a north-south axis.

But no one has yet been able to prove that that subconscious awareness of magnetic fields exists in humans — until now. Joe Kirschvink of the California Institute of Technology thinks he might be the first person to confirm that humans also have what he calls this “sixth sense.”

California Institute of Technology

Kirschvink’s study is still in its early stages — his sample size is small, and the work hasn’t yet been peer-reviewed. But

Science Alert reports that he’s gotten past the hurdles that have stopped past researchers from proving that humans have what’s called magnetoreception.

The possibility of magnetoreception in humans could help us understand evolution, Kirschvink told Science magazine. “It’s part of our evolutionary history,” he said. “Magnetoreception may be the primal sense.”

Previous experiments on this subject have failed when the results couldn’t be verified or repeated. But Kirschvink said he’s discovered that electromagnetic interference, which can come from computers, mobile devices, and elevators, among other everyday objects, can scramble results. So he prevented that interference by building what’s called a Faraday cage: a box with magnetically shielded aluminum walls.

“The Faraday cage is key,” Kirschvink told Science. “It wasn’t until the last few years, after we put the damned Faraday shield in, that we went, ‘Wait a minute.’”

He started his experiment by connecting his human subjects up to monitors that chart their brain activity. Consistently, throughout the run of his experiments, Kirschvink recorded a sharp drop in brainwaves when the magnetic field rotated counter-clockwise — the same way the Earth’s does.

Patrick T. Fallon / Bloomberg

The drop in waves suggests a natural brain response: as Science puts it, “a set of neurons firing in response to the magnetic field.” To Kirschvink, the fact that the response occurred only when the field was rotated counter-clockwise, and not in a clockwise direction, indicates the polarity of the human magnetic compass.

There are competing theories about the causes of magnetoreception. But for now, Kirschvink is focused on proving that it exists in humans at all. He’s currently in Tokyo, trying to replicate the results of his initial study with Japanese neuroengineer Ayumu Matani. After that, he’s hoping for a traveling Faraday cage he can test at the magnetic equator.

The magnetic “sixth sense” is not vital to human survival, but understanding its impact might help us gather a better scientific understanding of ourselves, Kirschvink said. He likens the magnetic sense in humans to the wings of an ostrich: it’s a remnant of our past.